* Radiotap parser
*
* Copyright 2007 Andy Green <andy@warmcat.com>
+ * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* Alternatively, this software may be distributed under the terms of BSD
* license.
*
- * See README and COPYING for more details.
- *
- *
- * Modified for userspace by Johannes Berg <johannes@sipsolutions.net>
- * I only modified some things on top to ease syncing should bugs be found.
+ * See COPYING for more details.
*/
-
-#include "includes.h"
-
-#include "common.h"
#include "radiotap_iter.h"
-
-#define le16_to_cpu le_to_host16
-#define le32_to_cpu le_to_host32
-#define __le32 uint32_t
-#define ulong unsigned long
-#define unlikely(cond) (cond)
-#define get_unaligned(p) \
-({ \
- struct packed_dummy_struct { \
- typeof(*(p)) __val; \
- } __attribute__((packed)) *__ptr = (void *) (p); \
- \
- __ptr->__val; \
-})
+#include "platform.h"
/* function prototypes and related defs are in radiotap_iter.h */
+static const struct radiotap_align_size rtap_namespace_sizes[] = {
+ [IEEE80211_RADIOTAP_TSFT] = { .align = 8, .size = 8, },
+ [IEEE80211_RADIOTAP_FLAGS] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_RATE] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_CHANNEL] = { .align = 2, .size = 4, },
+ [IEEE80211_RADIOTAP_FHSS] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_DBM_ANTNOISE] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_LOCK_QUALITY] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_TX_ATTENUATION] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_DBM_TX_POWER] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_ANTENNA] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_DB_ANTNOISE] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_RX_FLAGS] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_TX_FLAGS] = { .align = 2, .size = 2, },
+ [IEEE80211_RADIOTAP_RTS_RETRIES] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_DATA_RETRIES] = { .align = 1, .size = 1, },
+ [IEEE80211_RADIOTAP_MCS] = { .align = 1, .size = 3, },
+ [IEEE80211_RADIOTAP_AMPDU_STATUS] = { .align = 4, .size = 8, },
+ /*
+ * add more here as they are defined in radiotap.h
+ */
+};
+
+static const struct ieee80211_radiotap_namespace radiotap_ns = {
+ .n_bits = sizeof(rtap_namespace_sizes) / sizeof(rtap_namespace_sizes[0]),
+ .align_size = rtap_namespace_sizes,
+};
+
/**
* ieee80211_radiotap_iterator_init - radiotap parser iterator initialization
* @iterator: radiotap_iterator to initialize
* get_unaligned((type *)iterator.this_arg) to dereference
* iterator.this_arg for type "type" safely on all arches.
*
- * Example code:
- * See Documentation/networking/radiotap-headers.txt
+ * Example code: parse.c
*/
int ieee80211_radiotap_iterator_init(
- struct ieee80211_radiotap_iterator *iterator,
- struct ieee80211_radiotap_header *radiotap_header,
- int max_length)
+ struct ieee80211_radiotap_iterator *iterator,
+ struct ieee80211_radiotap_header *radiotap_header,
+ int max_length, const struct ieee80211_radiotap_vendor_namespaces *vns)
{
+ /* must at least have the radiotap header */
+ if (max_length < (int)sizeof(struct ieee80211_radiotap_header))
+ return -EINVAL;
+
/* Linux only supports version 0 radiotap format */
if (radiotap_header->it_version)
return -EINVAL;
/* sanity check for allowed length and radiotap length field */
- if (max_length < le16_to_cpu(get_unaligned(&radiotap_header->it_len)))
+ if (max_length < get_unaligned_le16(&radiotap_header->it_len))
return -EINVAL;
- iterator->rtheader = radiotap_header;
- iterator->max_length = le16_to_cpu(get_unaligned(
- &radiotap_header->it_len));
- iterator->arg_index = 0;
- iterator->bitmap_shifter = le32_to_cpu(get_unaligned(
- &radiotap_header->it_present));
- iterator->arg = (u8 *)radiotap_header + sizeof(*radiotap_header);
- iterator->this_arg = NULL;
+ iterator->_rtheader = radiotap_header;
+ iterator->_max_length = get_unaligned_le16(&radiotap_header->it_len);
+ iterator->_arg_index = 0;
+ iterator->_bitmap_shifter = get_unaligned_le32(&radiotap_header->it_present);
+ iterator->_arg = (uint8_t *)radiotap_header + sizeof(*radiotap_header);
+ iterator->_next_ns_data = NULL;
+ iterator->_reset_on_ext = 0;
+ iterator->_next_bitmap = &radiotap_header->it_present;
+ iterator->_next_bitmap++;
+ iterator->_vns = vns;
+ iterator->current_namespace = &radiotap_ns;
+ iterator->is_radiotap_ns = 1;
+#ifdef RADIOTAP_SUPPORT_OVERRIDES
+ iterator->n_overrides = 0;
+ iterator->overrides = NULL;
+#endif
/* find payload start allowing for extended bitmap(s) */
- if (unlikely(iterator->bitmap_shifter & (1<<IEEE80211_RADIOTAP_EXT))) {
- while (le32_to_cpu(get_unaligned((__le32 *)iterator->arg)) &
- (1<<IEEE80211_RADIOTAP_EXT)) {
- iterator->arg += sizeof(u32);
+ if (iterator->_bitmap_shifter & BIT(IEEE80211_RADIOTAP_EXT)) {
+ if ((unsigned long)iterator->_arg -
+ (unsigned long)iterator->_rtheader + sizeof(uint32_t) >
+ (unsigned long)iterator->_max_length)
+ return -EINVAL;
+ while (get_unaligned_le32(iterator->_arg) &
+ BIT(IEEE80211_RADIOTAP_EXT)) {
+ iterator->_arg += sizeof(uint32_t);
/*
* check for insanity where the present bitmaps
* stated radiotap header length
*/
- if (((ulong)iterator->arg - (ulong)iterator->rtheader)
- > (ulong)iterator->max_length)
+ if ((unsigned long)iterator->_arg -
+ (unsigned long)iterator->_rtheader +
+ sizeof(uint32_t) >
+ (unsigned long)iterator->_max_length)
return -EINVAL;
}
- iterator->arg += sizeof(u32);
+ iterator->_arg += sizeof(uint32_t);
/*
* no need to check again for blowing past stated radiotap
*/
}
+ iterator->this_arg = iterator->_arg;
+ iterator->this_arg_index = 0;
+ iterator->this_arg_size = 0;
+
/* we are all initialized happily */
return 0;
}
+static void find_ns(struct ieee80211_radiotap_iterator *iterator,
+ uint32_t oui, uint8_t subns)
+{
+ int i;
+
+ iterator->current_namespace = NULL;
+
+ if (!iterator->_vns)
+ return;
+
+ for (i = 0; i < iterator->_vns->n_ns; i++) {
+ if (iterator->_vns->ns[i].oui != oui)
+ continue;
+ if (iterator->_vns->ns[i].subns != subns)
+ continue;
+
+ iterator->current_namespace = &iterator->_vns->ns[i];
+ break;
+ }
+}
+
+#ifdef RADIOTAP_SUPPORT_OVERRIDES
+static int find_override(struct ieee80211_radiotap_iterator *iterator,
+ int *align, int *size)
+{
+ int i;
+
+ if (!iterator->overrides)
+ return 0;
+
+ for (i = 0; i < iterator->n_overrides; i++) {
+ if (iterator->_arg_index == iterator->overrides[i].field) {
+ *align = iterator->overrides[i].align;
+ *size = iterator->overrides[i].size;
+ if (!*align) /* erroneous override */
+ return 0;
+ return 1;
+ }
+ }
+
+ return 0;
+}
+#endif
+
/**
* ieee80211_radiotap_iterator_next - return next radiotap parser iterator arg
*/
int ieee80211_radiotap_iterator_next(
- struct ieee80211_radiotap_iterator *iterator)
+ struct ieee80211_radiotap_iterator *iterator)
{
-
- /*
- * small length lookup table for all radiotap types we heard of
- * starting from b0 in the bitmap, so we can walk the payload
- * area of the radiotap header
- *
- * There is a requirement to pad args, so that args
- * of a given length must begin at a boundary of that length
- * -- but note that compound args are allowed (eg, 2 x u16
- * for IEEE80211_RADIOTAP_CHANNEL) so total arg length is not
- * a reliable indicator of alignment requirement.
- *
- * upper nybble: content alignment for arg
- * lower nybble: content length for arg
- */
-
- static const u8 rt_sizes[] = {
- [IEEE80211_RADIOTAP_TSFT] = 0x88,
- [IEEE80211_RADIOTAP_FLAGS] = 0x11,
- [IEEE80211_RADIOTAP_RATE] = 0x11,
- [IEEE80211_RADIOTAP_CHANNEL] = 0x24,
- [IEEE80211_RADIOTAP_FHSS] = 0x22,
- [IEEE80211_RADIOTAP_DBM_ANTSIGNAL] = 0x11,
- [IEEE80211_RADIOTAP_DBM_ANTNOISE] = 0x11,
- [IEEE80211_RADIOTAP_LOCK_QUALITY] = 0x22,
- [IEEE80211_RADIOTAP_TX_ATTENUATION] = 0x22,
- [IEEE80211_RADIOTAP_DB_TX_ATTENUATION] = 0x22,
- [IEEE80211_RADIOTAP_DBM_TX_POWER] = 0x11,
- [IEEE80211_RADIOTAP_ANTENNA] = 0x11,
- [IEEE80211_RADIOTAP_DB_ANTSIGNAL] = 0x11,
- [IEEE80211_RADIOTAP_DB_ANTNOISE] = 0x11,
- [IEEE80211_RADIOTAP_RX_FLAGS] = 0x22,
- [IEEE80211_RADIOTAP_TX_FLAGS] = 0x22,
- [IEEE80211_RADIOTAP_RTS_RETRIES] = 0x11,
- [IEEE80211_RADIOTAP_DATA_RETRIES] = 0x11,
- /*
- * add more here as they are defined in
- * include/net/ieee80211_radiotap.h
- */
- };
-
- /*
- * for every radiotap entry we can at
- * least skip (by knowing the length)...
- */
-
- while (iterator->arg_index < (int) sizeof(rt_sizes)) {
+ while (1) {
int hit = 0;
- int pad;
+ int pad, align, size, subns;
+ uint32_t oui;
+
+ /* if no more EXT bits, that's it */
+ if ((iterator->_arg_index % 32) == IEEE80211_RADIOTAP_EXT &&
+ !(iterator->_bitmap_shifter & 1))
+ return -ENOENT;
- if (!(iterator->bitmap_shifter & 1))
+ if (!(iterator->_bitmap_shifter & 1))
goto next_entry; /* arg not present */
+ /* get alignment/size of data */
+ switch (iterator->_arg_index % 32) {
+ case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
+ case IEEE80211_RADIOTAP_EXT:
+ align = 1;
+ size = 0;
+ break;
+ case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
+ align = 2;
+ size = 6;
+ break;
+ default:
+#ifdef RADIOTAP_SUPPORT_OVERRIDES
+ if (find_override(iterator, &align, &size)) {
+ /* all set */
+ } else
+#endif
+ if (!iterator->current_namespace ||
+ iterator->_arg_index >= iterator->current_namespace->n_bits) {
+ if (iterator->current_namespace == &radiotap_ns)
+ return -ENOENT;
+ align = 0;
+ } else {
+ align = iterator->current_namespace->align_size[iterator->_arg_index].align;
+ size = iterator->current_namespace->align_size[iterator->_arg_index].size;
+ }
+ if (!align) {
+ /* skip all subsequent data */
+ iterator->_arg = iterator->_next_ns_data;
+ /* give up on this namespace */
+ iterator->current_namespace = NULL;
+ goto next_entry;
+ }
+ break;
+ }
+
/*
* arg is present, account for alignment padding
- * 8-bit args can be at any alignment
- * 16-bit args must start on 16-bit boundary
- * 32-bit args must start on 32-bit boundary
- * 64-bit args must start on 64-bit boundary
- *
- * note that total arg size can differ from alignment of
- * elements inside arg, so we use upper nybble of length
- * table to base alignment on
*
- * also note: these alignments are ** relative to the
- * start of the radiotap header **. There is no guarantee
+ * Note that these alignments are relative to the start
+ * of the radiotap header. There is no guarantee
* that the radiotap header itself is aligned on any
* kind of boundary.
*
- * the above is why get_unaligned() is used to dereference
- * multibyte elements from the radiotap area
+ * The above is why get_unaligned() is used to dereference
+ * multibyte elements from the radiotap area.
*/
- pad = (((ulong)iterator->arg) -
- ((ulong)iterator->rtheader)) &
- ((rt_sizes[iterator->arg_index] >> 4) - 1);
+ pad = ((unsigned long)iterator->_arg -
+ (unsigned long)iterator->_rtheader) & (align - 1);
if (pad)
- iterator->arg +=
- (rt_sizes[iterator->arg_index] >> 4) - pad;
+ iterator->_arg += align - pad;
+
+ if (iterator->_arg_index % 32 == IEEE80211_RADIOTAP_VENDOR_NAMESPACE) {
+ int vnslen;
+
+ if ((unsigned long)iterator->_arg + size -
+ (unsigned long)iterator->_rtheader >
+ (unsigned long)iterator->_max_length)
+ return -EINVAL;
+
+ oui = (*iterator->_arg << 16) |
+ (*(iterator->_arg + 1) << 8) |
+ *(iterator->_arg + 2);
+ subns = *(iterator->_arg + 3);
+
+ find_ns(iterator, oui, subns);
+
+ vnslen = get_unaligned_le16(iterator->_arg + 4);
+ iterator->_next_ns_data = iterator->_arg + size + vnslen;
+ if (!iterator->current_namespace)
+ size += vnslen;
+ }
/*
* this is what we will return to user, but we need to
* move on first so next call has something fresh to test
*/
- iterator->this_arg_index = iterator->arg_index;
- iterator->this_arg = iterator->arg;
- hit = 1;
+ iterator->this_arg_index = iterator->_arg_index;
+ iterator->this_arg = iterator->_arg;
+ iterator->this_arg_size = size;
/* internally move on the size of this arg */
- iterator->arg += rt_sizes[iterator->arg_index] & 0x0f;
+ iterator->_arg += size;
/*
* check for insanity where we are given a bitmap that
* max_length on the last arg, never exceeding it.
*/
- if (((ulong)iterator->arg - (ulong)iterator->rtheader) >
- (ulong) iterator->max_length)
+ if ((unsigned long)iterator->_arg -
+ (unsigned long)iterator->_rtheader >
+ (unsigned long)iterator->_max_length)
return -EINVAL;
- next_entry:
- iterator->arg_index++;
- if (unlikely((iterator->arg_index & 31) == 0)) {
- /* completed current u32 bitmap */
- if (iterator->bitmap_shifter & 1) {
- /* b31 was set, there is more */
- /* move to next u32 bitmap */
- iterator->bitmap_shifter = le32_to_cpu(
- get_unaligned(iterator->next_bitmap));
- iterator->next_bitmap++;
- } else
- /* no more bitmaps: end */
- iterator->arg_index = sizeof(rt_sizes);
- } else /* just try the next bit */
- iterator->bitmap_shifter >>= 1;
+ /* these special ones are valid in each bitmap word */
+ switch (iterator->_arg_index % 32) {
+ case IEEE80211_RADIOTAP_VENDOR_NAMESPACE:
+ iterator->_reset_on_ext = 1;
+
+ iterator->is_radiotap_ns = 0;
+ /*
+ * If parser didn't register this vendor
+ * namespace with us, allow it to show it
+ * as 'raw. Do do that, set argument index
+ * to vendor namespace.
+ */
+ iterator->this_arg_index =
+ IEEE80211_RADIOTAP_VENDOR_NAMESPACE;
+ if (!iterator->current_namespace)
+ hit = 1;
+ goto next_entry;
+ case IEEE80211_RADIOTAP_RADIOTAP_NAMESPACE:
+ iterator->_reset_on_ext = 1;
+ iterator->current_namespace = &radiotap_ns;
+ iterator->is_radiotap_ns = 1;
+ goto next_entry;
+ case IEEE80211_RADIOTAP_EXT:
+ /*
+ * bit 31 was set, there is more
+ * -- move to next u32 bitmap
+ */
+ iterator->_bitmap_shifter =
+ get_unaligned_le32(iterator->_next_bitmap);
+ iterator->_next_bitmap++;
+ if (iterator->_reset_on_ext)
+ iterator->_arg_index = 0;
+ else
+ iterator->_arg_index++;
+ iterator->_reset_on_ext = 0;
+ break;
+ default:
+ /* we've got a hit! */
+ hit = 1;
+ next_entry:
+ iterator->_bitmap_shifter >>= 1;
+ iterator->_arg_index++;
+ }
/* if we found a valid arg earlier, return it now */
if (hit)
return 0;
}
-
- /* we don't know how to handle any more args, we're done */
- return -ENOENT;
}
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